You need to memorize the basic css properties and look at different html layouts.
Try searching for e.g. 3 layer column website tutorials....Along the lines of that.
The best way to create websites manually is to color code every DIV. So lets say you have a header make the backgournd red, Intro = blue, navigation = green, main-content= yellow, footer = pink etc.
Now you can see the layout for what it is, put your content on, style it bit by bit without loosing track.
If you're doing it this way. Before you start you need to get a notepad and draw out the layout of every page, label every page, every link, button image place etc.
It's boring and you will realise that your website is more complex then it will appear.
But you will be able to make it look pretty.
Make sure you validate your code via W3C website. But don't trust it's correction tool it will mess up your code, manually adjust it.
There's so much more I can say but,...you will figure it out.